Heater



R. I. SCHANTZ March 3, 1970 HEATER 2 Sheets-Sheet 1 Filed Dec. 18 1967INVENTOR IPOBfiT I 5Z'M4A/TZ injfmm A ORNEY United States Patent3,498,732 HEATER Robert I. Schantz, 1633 SW. 164th St., Burien, Wash.98166 Filed Dec. 18, 1967, Ser. No. 691,456 Int. Cl. F2311 /00 US. Cl.43180 6 Claims ABSTRACT OF THE DISCLOSURE A catalytic gaseous spaceheater has a closed-loop, perforated gas distribution conduit extendingbetween two outlets of :a control valve. During initiation of burning,the conduit is oppositely supplied with gas. A pilot flame near one endof the conduit heats a thermo-couple valve control. Upon excitation ofthe valve control and the relief of manual pressure, the gas supply toone end of the conduit terminates, the pilot flame is extinguished, andthe heater operates on gas from a single outlet.

BACKGROUND Catalytic heaters operating on the principle of flamelesscombustion of carbon compounds containing gaseous vapors are, of course,known. In such heaters the catalyst which may be platinum or rhodium orpalladium on asbestos fiber in the form of a felt or fabric which isdisposed in a flat plane usually against a reticulated member and backedby a diffusing pad of glass wool or the like. A chamber encloses theassembly in which there also is a distribution conduit from which thegas exits and diffuses through to the asbestos face where it iscombusted. It is customary for the distribution conduit to be under thecontrol of a reciprocating, spring-biased-to-close valve. Such a systemusually includes a thermo-electric, magnetic assembly for maintainingthe distribution valve element open against its bias so long as heat isavailable. The heat effective on the thermo-couple is commonly a pilotflame also supplied through the control valve. This flame burns visiblyall during operation of the heater but this is undesirable and has beenfound unnecessary.

It has been an object of this invention to supply gas and so distributeand diffuse it that a broad field, flameless combustion can bemaintained, but dispensing with the usual pilot flame except upon abrief period during ignition of the gas heater when its operation isstarted. Put another way, this invention has for a main object theprovision of a completely flameless catalytic heater which is capable ofrapid ignition, safe operation by reason of complete combustion withoutdangerous carbon monoxide production, a high degree of control over theheat output, especially at lower levels and the provision of atwo-outlet valve, one of which outlets may be closed once combustion hasbeen established.

These and other objects will become apparent during the course of thefollowing description.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a perspective view of acatalytic heater constructed in accordance with the teachings of thepresent invention;

FIGURE 2 is a front elevation view showing the gas distribution tubingand the starter or main control valves of the heater shown in FIGURE 1;

FIGURE 3 is a fragmentary front elevation view, partly in section,showing a portion of the gas distribution tubing;

FIGURE 4 is a fragmentary, cross sectional view showing a portion of theinterior structure of the heater; and

FIGURES 57 are cross sectional views showing the main valve of theheater in its at-rest, starting and operating conditions, respectively.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGURES 1-4, acatalytic heater 10, constructed according to the present invention, isseen to comprise a casing. 12 having an enlarged window opening 14 inthe front panel 16 thereof covered by a protective grill 18. Throughsuitable openings in the front panel 16 protrudes rotary knob 20 forcontrol valve 22 and pushbutton 24 for the starter or pilot valve 26.Valves 22 and 26 are mounted within casing 12 and gas inlet tube 28extends to and past the control valve 22 and is connected to the inletside of starter valve 26. A closed loop gas distribution tube 32 isconnected at each end to passages on the outlet side of starter valve26. Pilot tube 30 extends from loop 32 to adjacent valve 22. As bestshown in FIGURE 4, the gas distribution tube 32 has a series of spacedpreferably rearwardly-facing, gas outlet orifices 34. The pilot tube 30terminates at the outlet 114 adjacent probe 36 of thermo-couple 58mounted on starter valve 26.

Insert plug 38 is disposed within the gas distribution tube 32 to cutoif the flame on pilot 114 when button 24 is released. As shown inFIGURE 3, the insert 38 comprises a cylindrical plug having a minuteorifice 40 extending axially therethrough. If plug 38 were eliminatedthere could be a gas flow to the pilot 114 even though gas flow :atpassage 54 is blocked.

Referring to FIGURE 4, the gas distribution tubing loop 32 is showndisposed adjacent the rear wall 42 of heater casing 12 with the orifices34 in the tubing facing rearwardly. A gas pervious sheet of material 44,such as glass wool, is sandwiched between the tubing and a fonaminouscatalytic fabric 46 (such as asbestos cloth including a metal catalyst,such as platinum, palladium or rhodium, incorporated therewith). Thewool sheet 44 functions to uniformly diffuse and distribute gas to thecatalytic fabric 46, and also serves an insulating function in theheater.

A relatively coarse or large mesh screen 48 extends over the forwardsurface of the catalyst 46 and protects as Well as holds it in place.

Referring to FIGURES 5-7, the starter valve 26 comprises casing 49having an inlet port 50, a main outlet port 52, a pilot outlet port 54and a chamber 56 housing a thermally-responsive electromagnetic assembly58'. A partition structure 60 separates the inlet port 50 from the mainand pilot outlet ports 52, 54. A passage 62 communicates between theinlet port 50 and a first or main opening 64 which, in turn,communicates with the main outlet port 52 via passage 66. The mainopening 64 is normally covered by a main valve closure 70 seated thereonand maintained in such seated position by spring 72 disposed between theclosure 70 and the electromagnetic assembly 58.

A second or pilot opening 74, smaller than the main opening 64, isdisposed between the main opening and the pilot outlet part 54. Pilotopening 74 is normally closed by the enlarged inner end 76 of aspool-type. valve closure 78. The enlarged outer end 77 of the spoolvalve 78 is connected by stem 80 to pushbutton 24. Spring 84 disposedbetween the button 24 and an annular surface 86 on the casing 49normally maintains the spool valve in the position shown in FIGURES 5and 7, wherein the enlarged inner end 76 closes pilot opening 74. O-ringin the wall of opening seals with valve end 76. When the button 24 ispushed inwardly, the spool valve 78 will be moved against the force ofthe spring 84.

As shown in FIGURE 6, as the spool 78 moves inwardly, the smallercentral portion 88 thereof will be disposed in the pilot opening 74,spanning O-ring 75. The inner valve end 76 then unseats the main valveclosure 70. With the valve closures so positioned, communication isestablished between the inlet port 50, the main opening 64, the mainoutlet passage 66 and port 52 and through the pilot opening 74 with thepilot outlet port 54.

Axial movement of stem 80 of the spool valve 78 is guided by annularboss 90 through which the stern slides. Annular collar 92 on body 26 isdisposed concentrically around boss 90 and guides movement of thepush-button 24. Spring 84 is seated in the annular channel 96 formed byboss 90 and flange 92 and exerts force on button 24.

The electromagnetic assembly 58 is conventional per se. It functions tomaintain the main valve closure 70 in its unseated position (FIGURE 7)when temperature at the face of the catalytic fabric 46 is above apredetermined level. The assembly includes the thermocouple probe 36,positioned in the vicinity of the catalytic fabric (see FIG- URES 1 and2), an electromagnetic core 98 disposed within the casing 49 (see FIGURE5), an energizing coil 100 wrapped around one pole of the core andconnected to the thermocouple probe 36. Armature 102, connected to themain valve closure 70 by means of stem 104, is adapted to be attractedtoward the poles of core 98.

As shown in FIGURE 5, the main and pilot outlet ports 52 and 54 areinternally threaded and closed by threaded fittings 106 and 108 havingminute longitudinal orifices 110 and 112 therethrough. Such orificesdictate the velocity and volume of gas flowing into the pilot tube andlooped distribution tubing 32.

Typically, the size of the several orifices in the heater may be asfollows:

ASME No. Orifice 110 in fitting 106 70 Orifice 110 in fitting 108 7lOrifice in plug 38 65 Orifice 34 in gas distribution tubing 32 upperrows lower rows 72 Outlet opening 114 in the pilot tube 30 may be thesize of an ASME No. 74 drill.

For operation, the heater is started by pressing inwardly thepush-button 24 of starter valve 26 and holding an ignition flame (suchas a lighted match adjacent the outlet orifice 114 of the tube 30 toignite gaseous fuel issuing therefrom. When button 24 is pushedinwardly, the spool valve 78 moves into the position shown in FIGURE 6,simultaneously bringing the smaller central or neckeddown portion 88 ofthe spool 78 into registry with the pilot opening 74 and unseats themain valve closure 70.

With communication between the inlet port 50 and the outlet ports 52 and54 thus established, gas under pressure flows from the inlet ports andthrough both outlet ports in the direction of the arrows shown in FIGURE6.

The ignited gas at the outlet 114 of pilot tube 30 heats thethermocouple 36 and generates electric current in coil 100 to energizethe core 98. When so energized, the core will magnetically attract thearmature 102 toward contact therewith.

The gas flowing through the main outlet port 52 will flow through thegas distribution loop 32 and the orifices 34 therein. Also, upon initialburning, gas may flow through the system throughout the outlet port 54when open. Plug 38 functions somewhat as a check and may be replaced bya check valve stopping gas flow from part 52 toward pilot 114 when port54 is closed.

As gas flows through the orifices 34 in looped tubing 32', it impingeson the rear plate 42 of casing 12 (see FIGURE 4) and flows and diffusesforwardly through wool matting 44, The matting quite evenly distributesthe gas flowing therethrough. From the matting the gas percolatesthrough the catalytic fabric 46 where it undergoes substantiallyfiameless combustion and heat which radiates forwardly through thescreen 48 and grill 18. So long as the temperature on the forward sideof the catalytic fabric 46 is above a predetermined level, thethermocouple 58 will maintain the electromagnetic core 98 energized andmagnetically attract the armature 102 holding main valve closure 70 ofstarter valve 26 in the raised position shown in FIGURE 7. Thepushbutton 24 may very shortly after ignition be released to allowspring 84 to retract the spool valve 78 to its closed position (FIG- URE7) wherein it blocks gas flow to the pilot outlet port 54 and pilottubing 30. Since the main valve closure 70 is held unseated to uncoverthe main valve opening 64 simultaneously with the uncovering of thepilot opening 74, gas will immediately flow through the loopeddistribution tubing 32 and catalytic fabric 46 as well as through thepilot opening 114, thereby speeding the generation of heat. Startervalve pushbutton 24 need only be held inwardly for a short period oftime.

During operation of the heater the temperature may be controlled byadjusting the rotary control valve knob 20 to increase or decrease theflow of gas from its source through the heater.

If the gas flowing through the catalytic fabric 45 should fail tocombust at any time after the pushbutton 24 has been released, thetemperature in the vicinity of the thermocouple will lower, therbyde-energizing the electromagnetic core 98 and permitting the spring 72to return the main valve closure 70 to its seated (FIGURE 5) position.Gas flow through the valve main openin 64 and to the main valve outletports 52 and 54 is then blocked and no harmful gas fumes will issue fromthe heater. The starter valve must be actuated again in the mannerdescribed above to restart the heater.

It will be apparent to those skilled in the art that changes andmodifications may be made within the skill of the art without departingfrom the spirit and scope of the invention as set forth in the subjoinedclaims.

What is claimed is:

1. In combination, a catalytic heater comprising:

a catalytic, gas-pervious barrier comprising a thermallyresistant clothhaving a plurality of gas passages therethrough and a catalytic metalincorporated therewith and a closed loop gas conduit serially perforatedto distribute gaseous fuel through and over the surface of saidcatalytic barrier; and

a valve for initiating the flow of gaseous fuel to said gas conduitmeans; said improved valve, comprising;

a valve casing having an inlet port, a main outlet port and a pilotoutlet port;

partition means separating said inlet port from said main and pilotoutlet ports;

a main opening in said partition means communicating with said mainoutlet port;

a main valve closure normally seated to cover said main opening andblock communication between said inlet port and said main outlet port;

a pilot opening in said partition means between said main opening andsaid pilot outlet port;

a pilot valve closure normally covering said p-ilot open- .ing to blockcommunication between said main opening and said pilot outlet port;

manually-operable means associated with said pilot valve closure formoving said pilot valve closure to a position wherein it simultaneouslyopens said pilot outlet port and unseats said main valve closure toestablish communication between said inlet port and said main and pilotoutlet ports;

thermally-operable electromagnetic means associated with said main valveclosure for maintaining said main valve closure in its unseated positionwhen the temperature of the gas passing through said catalytic barrieris above a predetermined level; and

said closed loop gas conduit having its ends coupled one to said mainand the other to said pilot outlet ports.

2. The structure according to claim 1 in which the conduit is juxtaposedto said barrier so that said perforations are directed away therefrom.

3. The structure according to claim 1 in which there is a pilot nozzlein said conduit directed at said thermallyoperable means and moreclosely associated with said pilot outlet port than said main outletport.

4. The structure according to claim 3 in which there is a ported plug insaid conduit in the proximity of said pilot nozzle and there are noperforations in the conduit between said plug and the pilot outlet port.

5. In combination, a heater comprising a gas-pervious catalytic barrierand a closed loop gas supply conduit adapted to distribute gaseous fuelthrough and over the surface of said barrier; and a valve for initiatingand controlling gaseous fuel supply to said conduit, comprising:

a valve casing having an inlet port, a main outlet port and a pilotoutlet port;

partition means separating said inlet port from said main and pilotoutlet ports;

a main opening in said partition means communicating with said mainoutlet port;

a main valve closure normally seated to cover said main opening andblock communication between said inlet port and said main outlet port;

a pilot opening in said partition means between said main opening andsaid pilot outlet port;

a pilot valve closure normally covering said pilot opening to blockcommunication between said main opening and said pilot outlet port;

manually-operable means associated with said pilot valve closure formoving said pilot valve closure to a position wherein it simultaneouslyopens said pilot outlet port and unseats said main valve closure toestablish communication between said inlet port and said main and pilotoutlet ports;

thermally-operable electromagnetic means associated with said main valveclosure for maintaining said main valve closure in its unseated positionwhen the temperature of the gas passing through said catalytic barrieris above a predetermined level; and

said closed loop gas conduit having its ends coupled one to said mainand the other to said pilot outlet ports.

6. A heater, comprising:

means forming an open-face chamber including a main panel;

an elongated distribution tube shaped in a single plane to provide atortuous path of distribution between its ends, said tube being disposedwithin said chamber adjacent said main panel and having a series oflongitudinally spaced perforations therein directed at said main panel;

wool batt means in said chamber in juxtaposed contact with saiddistribution tube opposite said panel;

a foraminous catalytic barrier disposed at the face of said wool battmeans oppositely to said distribution tube;

and a single controllable means associated with both ends of saiddistribution tube for supplying gaseous fuel thereto at the initiationof combustion, and including means limiting gaseous fuel supply to asingle end of said distribution tube when substantial combustion at thecatalytic barrier is established.

References Cited UNITED STATES PATENTS 2,962,036 11/1960 Collins 431-54X 3,037,554 6/1962 Risse 431-328 X 3,107,721 10/1963 Therault 431-329 X3,114,410 12/1963 Schneider 431-328 X CHARLES J. MYHRE, Primary ExaminerUS. Cl. X.R.

